Fall 2017 Physics HW# VI-CH7: Momentum, Impulse, and Collisions

This document presents the solutions to Physics homework assignment HW# VI-CH7, focusing on the concepts of momentum, impulse, and collisions. The assignment includes problems involving bullet penetration into wood, tennis ball impacts, fullback tackles, croquet ball collisions, softball collisions, pendulum motion after bullet impact, and ballistic pendulum calculations. The solutions provide detailed calculations for determining velocities, impulses, forces, kinetic energy transfer, and displacement components in various collision scenarios. The problems cover both elastic and inelastic collisions, providing a comprehensive understanding of momentum and energy conservation principles.

12/14/2017 HW# VI-CH7
http://www.webassign.net/web/Student/Assignment-Responses/submit?dep=17452613 1/3
Current Score : 93.75 / 100 Due : Sunday, December 17 2017 07:00 PM EST
1. 12.5/12.5 points | Previous AnswersGiancoli7 7.P.011.
A 13 g bullet traveling 230 m/s penetrates a 2.0 kg block of wood and emerges cleanly at 167 m/s. If
the block is stationary on a frictionless surface when hit, how fast does it move after the bullet emerges?
0.4095 m/s
2. 6.25/12.5 points | Previous AnswersGiancoli7 7.P.018.
A tennis ball of mass m = 0.055 kg and speed v = 55 m/s strikes a wall at a 45° angle and rebounds
with the same speed at 45°. What is the impulse given to the wall?
Magnitude
4.278 N·s
Direction
HW# VI-CH7 (Homework)
EMILY BRODSKY
110, section 02, Fall 2017
Instructor: DESIRE MIESSEIN
WebAssign
in the direction of the ball's original motion
opposite the direction of the ball's original motion
normal and away from the wall
normal and into the wall
in the direction of the ball's final motion
opposite the direction of the ball's final motion

12/14/2017 HW# VI-CH7
http://www.webassign.net/web/Student/Assignment-Responses/submit?dep=17452613 2/3
3. 12.5/12.5 points | Previous AnswersGiancoli7 7.P.021.
A 125 kg fullback is running at 3.5 m/s to the east and is stopped in 0.75 s by a head-on tackle by a
tackler running due west.
(a) Calculate the original momentum of the fullback.
437.5 kg·m/s east
(b) Calculate the impulse exerted on the fullback.
437.5 kg·m/s west
(c) Calculate the impulse exerted on the tackler.
437.5 kg·m/s east
(d) Calculate the average force exerted on the tackler.
583.33 N east
4. 12.5/12.5 points | Previous AnswersGiancoli7 7.P.029.
A 0.200 kg croquet ball makes an elastic head-on collision with a second ball initially at rest. The second
ball moves off with half the original speed of the first ball.
(a) What is the mass of the second ball?
0.6 kg
(b) What fraction of the original kinetic energy ( ΔKE/KE) gets transferred to the second ball?
0.75
5. 12.5/12.5 points | Previous AnswersGiancoli7 7.P.031.
A softball of mass 0.220 kg that is moving with a speed of 4.0 m/s (in the positive direction) collides
head-on and elastically with another ball initially at rest. Afterward the incoming softball bounces
backward with a speed of 2.2 m/s.
(a) Calculate the velocity of the target ball after the collision.
1.799 m/s
(b) Calculate the mass of the target ball.
0.758 kg
6. 12.5/12.5 points | Previous AnswersGiancoli7 7.P.035.
An 18 g rifle bullet traveling 235 m/s buries itself in a 3.3 kg pendulum hanging on a 3.0 m long string,
which makes the pendulum swing upward in an arc. Determine the vertical and horizontal components of
the pendulum's displacement.
vertical 0.0829 m
horizontal 0.7003 m

12/14/2017 HW# VI-CH7
http://www.webassign.net/web/Student/Assignment-Responses/submit?dep=17452613 3/3
7. 12.5/12.5 points | Previous AnswersGiancoli7 7.P.042.
A gun is fired vertically into a 1.25 kg block of wood at rest directly above it. If the bullet has a mass of
21.0 g and a speed of 220 m/s, how high will the block rise into the air after the bullet becomes
embedded in it?
0.673 m
8. 12.5/12.5 points | Previous AnswersGiancoli7 7.P.078.
Two balls, of masses mA = 36 g and m B = 80 g are suspended as shown in the figure below. The lighter
ball is pulled away to a 60° angle with the vertical and released.
(a) What is the velocity of the lighter ball before impact? (Take the right to be positive.)
1.715 m/s
(b) What is the velocity of each ball after the elastic collision?
ball A -0.6488 m/s
ball B 1.065 m/s
(c) What will be the maximum height of each ball (above the collision point) after the elastic
collision?
ball A 0.0214 m
ball B 0.0578 m